paraglide-messages-mcp

An MCP server that turns AI agents into a parallel translation team for Paraglide JS / inlang messages/{locale}.json files.

The agent calling the tools is the translator. The server makes that safe and fast:

• Validated writes — every translation is checked against the source (placeholders, markup, plural variants) before anything lands on disk; bad items are rejected individually, never the whole batch.
• One agent per locale, in parallel — the translate loop reads and writes only the source and target locale's files, so subagents can translate all locales concurrently without conflicts.
• Fast and offline — direct JSON file access with a stat-validated cache; tool calls cost milliseconds regardless of project size, and no network is ever needed.
• Toolchain-invisible — written files are byte-compatible with the message-format plugin's own output, and external edits (editor, compiler, git) are always picked up.

Quick start

No installation — add this to your .mcp.json (Claude Code) or claude_desktop_config.json:

{
  "mcpServers": {
    "paraglide": {
      "command": "npx",
      "args": [
        "-y",
        "paraglide-messages-mcp",
        "--project",
        "./project.inlang",
        "--translation-style",
        "Concise product UI; informal address; keep brand terms untranslated."
      ]
    }
  }
}

--project is optional: the server finds project.inlang in the working directory (or a single *.inlang directory up to one level deep) by itself. --translation-style is optional but recommended: it gives agents the linguistic brief to use for tone, formality, and terminology instead of deriving style from existing translations.

Then ask your agent to translate — or use the translate_project prompt to translate every locale at once with one subagent per locale.

Tools

| Tool | Purpose | | --- | --- | | project_info | Locales, base locale, totalKeys across all locales, translatableKeys from non-empty base messages, per-locale translated/missing counts, extra non-source keys, and the startup translation style brief when configured. | | get_translation_batch | Next batch of untranslated messages for a locale (default 50), with source text and required placeholders. Optionally autosaves the previous batch in the same call (pass translations), so the loop is one round-trip per batch and the final batch is saved by the call that reports done. | | get_retranslation_batch | Cursor-paged batch over already-translated messages too — refresh stale entries after source/terminology changes. Same optional autosave as get_translation_batch. | | save_translations | Validate and persist translations for one locale; per-item results — overwrites existing values. (The batch tools share this save core for their autosave.) | | list_message_keys | Keys only, filterable by prefix and status, paginated. | | get_messages | Full message content by keys or prefix. | | search_messages | Find messages by text or key substring. | | delete_messages / rename_message | Key management across all locales. | | remove_orphan_messages | Delete target-locale keys that are absent from the source locale (base locale by default), optionally scoped by locale or prefix. | | add_locale / remove_locale | Locale management in settings.json. |

Prompts

| Prompt | Purpose | | --- | --- | | translate_project | Translate every locale: the main agent uses the startup translation style brief (or asks the user for one), then fans out one subagent per locale in parallel. | | translate_locale | Translate one locale via the batch loop. | | translate_prefix | Same, scoped to keys starting with a prefix. | | retranslate | Redo existing translations (stale copy, changed terminology) — by key prefix, every target locale by default, one subagent per locale. | | review_locale | Review existing translations against the base locale and fix problems. |

Read-only state is also exposed as MCP resources (paraglide://project/info, paraglide://locales/{locale}/missing, paraglide://messages/{locale}/{key}), so clients can pin it as context without spending tool calls.

Agent skill

skill/paraglide-translation/ is an optional installable skill in the open Agent Skills format. The skill simply points the agent to the MCP server.

# Codex, via the skills CLI
npx skills add whazeted/paraglide-messages-mcp --skill paraglide-translation -a codex

# Or install from the skill folder URL directly
npx skills add https://github.com/whazeted/paraglide-messages-mcp/tree/main/skill/paraglide-translation -a codex

For other skills-compatible agents, replace codex with that agent's skills CLI target name. You can list the skill before installing:

npx skills add whazeted/paraglide-messages-mcp --list

Compatibility

Requires the standard Paraglide JS setup: the inlang message format plugin with a single message file per locale (any pathPattern location). Other inlang plugins (i18next, next-intl, ICU) and multi-file namespaces are deliberately not supported — see COMPATIBILITY.md for the exact criteria and reasoning.

Performance

A full 10-locale translation run over a 5,000-message project costs ~3 s of server time (M1 Max Mac Studio)— the pipeline is bounded by the agent's translation speed, not the server.

Documentation

• DEVELOPMENT.md — architecture, message format details, validation rules, building, testing, benchmarking, releasing
• COMPATIBILITY.md — supported project setups

License

MIT